Amps to kVA Calculator
Convert amps to kilovolt-amps for single-phase and three-phase supplies — apparent power, so no power factor is needed.
How to use it
- Pick the supply type first — DC, AC single phase or AC three phase — because it changes the formula.
- Fill in the boxes; the answer and the substituted formula update as you type.
- Nothing is sent to a server, so you can use it offline once the page has loaded.
This calculator works out amps to kva from current and voltage. It shows the substituted formula underneath every result, so you can check the arithmetic or copy the working straight into a report.
The formula
S(kVA) = I × V ÷ 1000 · three phase: S = √3 × I × V ÷ 1000
DC, single phase and three phase
The supply type changes the formula, which is why it is the first thing to set. On DC there is no phase shift, so power is simply voltage times current. On AC single phase the power factor enters the calculation, because current and voltage may not peak together. On three phase, a factor of √3 — about 1.732 — appears as well, since the three conductors share the load.
Getting this wrong is the most common source of an answer that is out by 70%: that is exactly the √3 factor, applied or omitted by mistake.
About power factor
Power factor is the ratio of real power, in watts, to apparent power, in volt-amps. A heater or a filament lamp sits at 1.0 because it is purely resistive. An induction motor typically runs between 0.8 and 0.9, and lightly loaded it can fall much lower.
If you do not know the figure for your load, 0.8 is the conventional assumption for motors and 1.0 for pure heating. Use the real nameplate value where you have it, because sizing a cable on a guess is how installations end up running hot.
Everything runs in your browser
There is no server involved in the calculation. The numbers you type never leave your device, nothing is logged, and the page keeps working with no connection once it has loaded. That is not a marketing line — it is simply how the tool is built, because a calculation like this has no reason to touch a network.
Questions people ask
When do I need the power factor?
Only on AC. Power factor is the ratio of real power (watts) to apparent power (volt-amps). Resistive loads like heaters and filament lamps sit at 1; induction motors are typically 0.8. On DC there is no phase shift, so power factor does not apply.
What is the difference between single phase and three phase?
A three-phase supply delivers power on three conductors, so for the same line voltage and current it carries √3 (about 1.732) times more power. That factor appears in every three-phase formula on this page.
Is the calculation done on your servers?
No. Everything runs in your browser, so nothing you type is uploaded and the page keeps working with no connection.
Last updated 17 August 2026